The Euclid telescope accidentally discovered a new comet
Space telescopes are designed to solve specific scientific problems, but their observations sometimes lead to unexpected discoveries. The European Euclid spacecraft, designed to study dark matter and dark energy, has discovered a previously unknown comet at a distance of about 1.3 billion km from Earth. It was noticed thanks to a special computer program that looked for moving objects in the telescope images. About how astronomers found a comet where they did not plan to look for it — in the material of Izvestia.
An unexpected find
The European Euclid Space Telescope has discovered the first previously unknown comet during its operation. The object was designated C/2026 S1 (Euclid). The International Astronomical Union confirmed the discovery on October 8, 2026, after which information about the comet became available to researchers around the world. The discovery was announced by the European Space Agency (ESA) on its website.
The comet was spotted in images taken between September 16 and 24 as part of the Euclid's Northern deep field survey. It was located about 1.3 billion km from Earth, at a distance comparable to the gap between the orbits of Jupiter and Saturn. On long exposures, the object looked like an elongated streak of light against the background of stars and galaxies.
The discovery was made by Mikko Pentinen, a researcher from the University of Helsinki, who developed a program for detecting moving objects in telescope data. At first, the system noticed an unusual footprint moving between the images. Upon further study, the astronomer discovered a blurred cloud of dust and gas around it — a characteristic feature of an active comet.
Mikko Pentinen
I was pleased to see that my program had marked a "stripe" blurred across several images, the result of a fast object moving. Further investigation revealed that there was a blurry cloud around it, indicating the presence of an active object such as a comet dumping dust and gas.
How the discovery was confirmed
To determine the nature of the object, the researcher traced its position in several images and checked whether it corresponded to the movement of the comet. In total, the celestial body was found in five different fields of view. Additional observations allowed us to see the gas and dust shell surrounding it, which occurs when volatile comet substances are released into outer space.
Pentinen then transmitted the results to the Minor Planet Center of the International Astronomical Union. This organization collects and verifies information about asteroids and comets, helps calculate their orbits, and confirms new discoveries. A comparison with existing catalogs has shown that the object was previously unknown to astronomers.
The observations also made it possible to clarify the trajectory of the celestial body. Unlike planets that orbit the Sun in approximately the same plane, the new comet is moving far above this plane. Its orbit has a period of thousands of years, so the object's return to the inner Solar System is extremely rare.
Why wasn't the comet expected to be found
The Euclid telescope was launched in 2023 for a six-year mission to study dark matter and dark energy. To do this, the device must make a detailed map of billions of galaxies and track how they are distributed in space and change over time. Therefore, his observations are organized in such a way as to obtain clear images of distant objects. The telescope deliberately avoids the strip of sky along the plane of the Solar System, where many comets, asteroids and dust are concentrated. It can create unnecessary glare and interfere with observations of distant galaxies.
In addition, Euclid usually takes pictures of a certain area of the sky and then moves on to the next one, rather than returning to the same area on request. This makes it difficult to find moving objects that have time to change their position relative to stars and galaxies during observation.
Despite these limitations, Pentinen's program was able to identify an unusual footprint in the images and compare several observations. According to Bruno Altieri, a scientist at the Euclid archive, the probability of such discoveries was initially considered low.
Bruno Altieri
Euclid was expected to find very few comets, so it was a happy coincidence.
What the discovery will give astronomers
Although the search for comets is not the main task of Euclid, the discovery of C/2026 S1 showed that the telescope's data can also be used to study small objects in the Solar system. It is important to take their movement into account in order to separate the traces of comets and asteroids from the signals of distant galaxies and to avoid distortions in the construction of cosmological maps.
Comets are also of scientific interest in their own right. These are icy bodies that have preserved matter since the formation of the Solar System about 4.6 billion years ago. As the comet approaches the Sun, its ices heat up, releasing gas and dust. The study of such material helps to investigate the conditions in which planets were formed, and the origin of certain substances important for the origin of life.
The discovery was also a test of the interaction between the teams of different space projects: the Euclid data made it possible to detect the object, and ground-based observations helped confirm its nature. Although C/2026 S1 is not suitable for studying as part of ESA's future Comet Interceptor mission, the experience gained may be useful in detecting other comets.
Thus, the telescope, created to explore the largest mysteries of the universe, unexpectedly helped to find a new object in our own Solar system. This shows that even observations focused on one scientific task can open up opportunities for other fields of astronomy.
Переведено сервисом «Яндекс Переводчик»
